1. Field of the Invention
The present invention relates to a hopper and, more particularly, to a hopper structure to be used for supplying chip parts without terminals.
2. Description of the Prior Art
A hopper structure known in the prior art will be described with reference to FIG. 2.
Denoted at reference numeral 1 in FIG. 2 is a hopper body for holding chip parts 2 thrown thereinto. This hopper body 1 is mounted on a mounting bed 4 through a lining-up block 3. The mounting bed 4 has its end portion bent upright to form a support stand 4a which bears a drive roll 5 of rubber at its upper end.
Denoted at numeral 6 in FIG. 2 is a driven roll which has a portion exposed to the inside of the aforementioned hopper body 1. A weighted lid 7 is placed on the top of the hopper body 1 so that the driven roll 6 may be urged against the aforementioned drive roll 5. Moreover, the driven roll 6 is diametrically symmetrically cut off to form a pair of mixing projections 6a and 6a which are made movable in a floating state.
Still moreover, the lining-up block 3 underlying the hopper body 1 is formed with: a lining-up cylindrical hole 3a merging in alignment into the lower spout of the hopper body 1; and a chute 3b out of alignment with the lining-up cylindrical hole 3a. Between the chute 3b and the lining-up cylindrical hole 3a, there is interposed a shutter 3e which is formed with a through hole 3d and biased by a spring 3c to slide to the right and left.
The hopper structure of the prior art has the construction described above. The chip parts 2 are thrown into the hopper body 1, and the drive roll 5 is turned counter-clockwise, as indicated by an arrow. Then, the driven roll 6 urged by the drive roll 5 is turned clockwise, as indicated by an arrow, so that the chip parts 2 are so mixed by the mixing projections 6a and 6a extending from the driven roll 6 that they may be released from any entanglement until they are allowed to drop one by one into the lining-up cylindrical hole 3a of the lining-up block 3. The chip parts 2 thus lined up in the cylindrical hole 3a are delivered to slide one by one into the chute 3b by the through hole 3d of the shutter 3e.
In this hopper structure of the prior art, however, the mixing projections 6a and 6a are rubbed, while turning, by the lining-up block 3 and the hopper body 1 so that they are ground or buckled. Due to limitations to the shape of the mixing projections 6a and 6a, moreover, shavings are formed which deteriorate the reliabilities of the line-up, separation and dropping of the chip parts 2 and the mixing effect of the chip parts 2. As a result, the service life of the hopper is shortened.
In case a plurality of hoppers are to be driven by the single drive roll 5, this drive roll 5 is made of rubber so as to absorb the minute dispersions of the positional accuracy and diameter of the driven rolls 6. As a result, the drive roll 5 wears so that its tailings are trapped by the hopper body 1 to cause deterioration in the reliabilities of the line-up, separation and dropping of the chip parts 2. This shortens the lifetime of the drive roll 5 itself and makes it necessary to provide the weighted lid 7 for setting on the hopper. Due to the presence of the weighted lid 7, it takes additional time to disassemble the hopper, and the driven rolls 6 are seriously loaded so that the reliability of their turning movement is affected.